Screw-cutting die



(No Model.)

G. L. ENGGREN. SGR-.EW CUTTING DIE.v

No. 433,334. Patented July 29, 1890.

UNITED STATES PATENT OFFICE.A

GUS'IAV L. ENGGREN, OF BROOKLYN, NEW YORK.

SCREW-CUTTING DIE.

SPECFICATION forming part of Letters Patent No. 433,334, dated July 29,1890.

Application filed November l2, 1889. Serial No. 330,015. (No model.)

To all whom it may concern:

Be it known that I, GUSTAV L. ENGGREN, a citizen of the United States,residing at Brooklyn, in the county of Kings and State of New York, haveinvented certain new and useful Improvements in Screw-Cutting Dies; andI do hereby declare that the following is a full, clear, and exactdescription of the same, reference being had to the annexed drawing,making a part of this specification, and to the letters of referencemarked thereon.

Thisinvention relates to certain new and useful improvements in dies forcutting screws; and it has for its object to provide an improved diehaving a cut-out portion or space back of the cutting-points hollowedont in such manner that the friction is materially reduced at that partof the die without giving it any cutting-edge at this point, sothat inthe backward movement of the die no shavings are formed thereby; hencenothing to drag under and break and destroy the cutting-edge.

The novelty resides in the peculiarities of construction of the die, asmore fully hereinafter described, shown in the drawing, and thenparticularly pointed out in the appended claim.

The invention is clearly illustrated in the accompanying drawing, whichis a perspective View ot my improved die.

Referring to said drawing by letter, A designates the die formed withthe cutting points or edges B, between which are formed the spaces O toreceive the cuttings or shavings made in the process of cutting thescrew. Each cutting' point or edge is cut away, as shown at D, to formaspace, rounded, as shown, to dispense with or lessen friction,so thatthe die maybe turned backward with less exertion and to prevent itmaking any shavings in that part of the die. It will thus be seen thatany shavings that are formed in cutting the screw will be cleaned awayonturning the die backwardby the tooth back of the one that made theshaving, and as there are no shavings formed in the hollow back of thecutting-edge there will be nothing'to drag under and break thecutting-edge.

The die described, consisting of a plate having an opening therein, thecutting portions lrthe spaces D between each pair of eutters, and thespaces O, as set forth.

In testimony that I claim the above I have hereunto subscribed myname inthe presence of two witnesses.

GUSTAV L. ENGGREN. vWitnesses:

C. A. ENGGREN, H. MCLAUGHLIN.

